This invention concerns hydrocarbon fuel compositions containing divalent tetracoordinated cobalt complexes, referred to for simplicity as Co(II) bis(.beta.-acetyl-N-alkylvinylimines).
One of the most important performance properties of a gasoline for internal combustion engines is its antiknock quality. Antiknock quality determines the maximum power, efficiency, and economy that an engine can provide.
Antiknock quality, indicated by the octane number of a gasoline, can be improved by increasing the amount of high octane quality hydrocarbons such as benzene, toluene, etc. in the gasoline. However, because of their flexibility and economy, antiknock additives such as tetraalkyllead compounds have been used regularly by gasoline refiners to improve antiknock quality of hydrocarbon fuels.
With the advent of automobiles equipped with catalytic converters for exhaust emission control purposes has come the attendant requirement for lead-free gasolines. Reliance upon blending more of the high octane hydrocarbon components to improve the octane quality of the fuel is uneconomical since these hydrocarbon components are more valuable when utilized as solvents and as chemical feedstocks in the petrochemical industry.
Numerous nonlead antiknock additives, both metal-containing and metal-free, have been suggested in the art but have not attained practical significance because of insufficient antiknock activity, hydrolytic or oxidative instability, insufficient solubility or combinations of these deficiencies. Accordingly, there is a need for an effective and stable non-lead octane improving additive for the production of lead-free gasolines of good antiknock quality.
Cobalt-containing compounds are known for use in internal combustion engines as antiknocks, antipreignition agents and the like. Disclosures of such cobalt-containing compounds can be found in U.S. Pat. Nos. 2,023,372; 2,086,775; 2,737,932; 2,902,983; and 2,235,466, and in British Pat. No. 287,192. These patents do not, however, suggest the particular cobalt-containing compounds employed in this invention.
The complexes described herein are known from Everett and Holm, J. Am. Chem. Soc. 88 2442 (1966). Nowhere in the art, however, is there any suggestion that the Everett and Holm complexes might be useful as antiknock agents. More importantly, there is no suggestion that such compounds would be characterized by good antiknock activity, good hydrolytic and oxidative stability, and good solubility in hydrocarbon fuels.